diff --git a/packages/wasm-solana/eslint.config.js b/packages/wasm-solana/eslint.config.js
index 4ffa4ee..ac914ad 100644
--- a/packages/wasm-solana/eslint.config.js
+++ b/packages/wasm-solana/eslint.config.js
@@ -15,4 +15,29 @@ export default tseslint.config(
   {
     ignores: ["dist/", "pkg/", "target/", "node_modules/", "js/wasm/", "*.config.js"],
   },
+  // Ban Node.js globals in production code
+  {
+    files: ["js/**/*.ts"],
+    rules: {
+      "no-restricted-globals": [
+        "error",
+        {
+          name: "Buffer",
+          message: "Use Uint8Array instead of Buffer for ESM compatibility.",
+        },
+        {
+          name: "process",
+          message: "Avoid Node.js process global for ESM compatibility.",
+        },
+        {
+          name: "__dirname",
+          message: "Use import.meta.url instead of __dirname for ESM.",
+        },
+        {
+          name: "__filename",
+          message: "Use import.meta.url instead of __filename for ESM.",
+        },
+      ],
+    },
+  },
 );
diff --git a/packages/wasm-solana/js/transaction.ts b/packages/wasm-solana/js/transaction.ts
index 8e3ec4f..ecfd35b 100644
--- a/packages/wasm-solana/js/transaction.ts
+++ b/packages/wasm-solana/js/transaction.ts
@@ -116,11 +116,10 @@ export class Transaction {
   /**
    * Serialize the message portion of the transaction.
    * Alias for signablePayload() - provides compatibility with @solana/web3.js API.
-   * Returns a Buffer for compatibility with code expecting .toString('base64').
-   * @returns The serialized message bytes as a Buffer
+   * @returns The serialized message bytes
    */
-  serializeMessage(): Buffer {
-    return Buffer.from(this.signablePayload());
+  serializeMessage(): Uint8Array {
+    return this.signablePayload();
   }
 
   /**
diff --git a/packages/wasm-solana/js/versioned.ts b/packages/wasm-solana/js/versioned.ts
index 1df22a2..2c14909 100644
--- a/packages/wasm-solana/js/versioned.ts
+++ b/packages/wasm-solana/js/versioned.ts
@@ -82,14 +82,6 @@ export class VersionedTransaction {
     return new VersionedTransaction(WasmVersionedTransaction.from_bytes(bytes));
   }
 
-  /**
-   * Deserialize a transaction from base64 string.
-   */
-  static fromBase64(base64: string): VersionedTransaction {
-    const bytes = Uint8Array.from(Buffer.from(base64, "base64"));
-    return VersionedTransaction.fromBytes(bytes);
-  }
-
   /**
    * Create a VersionedTransaction from a WasmVersionedTransaction instance.
    * @internal Used by builder functions
@@ -188,11 +180,10 @@ export class VersionedTransaction {
   /**
    * Serialize the message portion of the transaction.
    * Alias for signablePayload() - provides compatibility with @solana/web3.js API.
-   * Returns a Buffer for compatibility with code expecting .toString('base64').
-   * @returns The serialized message bytes as a Buffer
+   * @returns The serialized message bytes
    */
-  serializeMessage(): Buffer {
-    return Buffer.from(this.signablePayload());
+  serializeMessage(): Uint8Array {
+    return this.signablePayload();
   }
 
   /**
@@ -202,13 +193,6 @@ export class VersionedTransaction {
     return this.inner.to_bytes();
   }
 
-  /**
-   * Serialize the transaction to base64.
-   */
-  toBase64(): string {
-    return Buffer.from(this.toBytes()).toString("base64");
-  }
-
   /**
    * Serialize to network broadcast format.
    * @returns The transaction as bytes ready for broadcast
diff --git a/packages/wasm-solana/test/versioned.ts b/packages/wasm-solana/test/versioned.ts
index b9e9443..86e668c 100644
--- a/packages/wasm-solana/test/versioned.ts
+++ b/packages/wasm-solana/test/versioned.ts
@@ -1,6 +1,16 @@
 import * as assert from "assert";
 import { VersionedTransaction, isVersionedTransaction } from "../js/versioned.js";
 
+/** Helper to decode base64 in tests (Buffer is allowed in tests) */
+function base64ToBytes(base64: string): Uint8Array {
+  return Uint8Array.from(Buffer.from(base64, "base64"));
+}
+
+/** Helper to encode bytes to base64 in tests */
+function bytesToBase64(bytes: Uint8Array): string {
+  return Buffer.from(bytes).toString("base64");
+}
+
 describe("VersionedTransaction", () => {
   // Legacy transaction (same as transaction.ts test)
   const LEGACY_TX_BASE64 =
@@ -15,7 +25,7 @@ describe("VersionedTransaction", () => {
 
   describe("legacy transaction parsing", () => {
     it("should parse legacy transaction as versioned", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
 
       assert.strictEqual(tx.isVersioned, false);
       assert.ok(tx.feePayer);
@@ -23,14 +33,14 @@ describe("VersionedTransaction", () => {
     });
 
     it("should have empty address lookup tables for legacy", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
       const alts = tx.addressLookupTables();
 
       assert.strictEqual(alts.length, 0);
     });
 
     it("should have static account keys", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
       const keys = tx.staticAccountKeys();
 
       assert.ok(Array.isArray(keys));
@@ -40,7 +50,7 @@ describe("VersionedTransaction", () => {
     });
 
     it("should get instructions", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
       const instructions = tx.instructions();
 
       assert.ok(Array.isArray(instructions));
@@ -53,7 +63,7 @@ describe("VersionedTransaction", () => {
     });
 
     it("should get signable payload", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
       const payload = tx.signablePayload();
 
       assert.ok(payload instanceof Uint8Array);
@@ -61,7 +71,7 @@ describe("VersionedTransaction", () => {
     });
 
     it("should roundtrip", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
       const bytes = tx.toBytes();
 
       const tx2 = VersionedTransaction.fromBytes(bytes);
@@ -71,7 +81,7 @@ describe("VersionedTransaction", () => {
     });
 
     it("should add signature", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
       const feePayer = tx.feePayer;
 
       const signature = new Uint8Array(64).fill(42);
@@ -85,10 +95,10 @@ describe("VersionedTransaction", () => {
 
   describe("base64 serialization", () => {
     it("should roundtrip base64", () => {
-      const tx = VersionedTransaction.fromBase64(LEGACY_TX_BASE64);
-      const base64 = tx.toBase64();
+      const tx = VersionedTransaction.fromBytes(base64ToBytes(LEGACY_TX_BASE64));
+      const base64 = bytesToBase64(tx.toBytes());
 
-      const tx2 = VersionedTransaction.fromBase64(base64);
+      const tx2 = VersionedTransaction.fromBytes(base64ToBytes(base64));
       assert.strictEqual(tx.feePayer, tx2.feePayer);
     });
   });